Apparatus and associated method for communicating multimedia information upon a communication link

ABSTRACT

Apparatus, and associated method, converts real-time multimedia information generated pursuant to an RTP protocol into a form amenable for transmission upon a radio channel, such as a radio channel defined in a cellular communication system. When converted, the informational content of the multimedia information is transmitted in a manner that achieves spectral efficiency and low, constant delay. Once transmitted over the radio channel, the multimedia information is converted back into form corresponding to the RTP protocol before being sent to the receiving station.

[0001] The present invention relates generally to the communication ofmultimedia information, such as multimedia information formattedpursuant to the RealTime Transport Protocol (RTP). More particularly,the present invention relates to apparatus, and an associated method,for converting realtime multimedia information, formatted in packet dataform, such as that formatted pursuant to the RTP, into a form tofacilitate transmission of the information on a radio channel. Operationof an embodiment of the present invention permits the communication ofmultimedia information by way of a cellular, or other radiocommunication system, with minimal and constant time delay while alsocommunicating the information in a spectrally-efficient manner.

BACKGROUND OF THE INVENTION

[0002] Advancements in communication technologies have permitted theintroduction of, and popularization of, new types of, and improvementsin existing, communication systems. Increasingly large amounts of dataare permitted to be communicated at increasing thruput rates through theuse of such new, or improved, communication systems. As a result of suchimprovements, new types of communications, requiring high data thruputrates, are possible. Digital communication techniques, for instance, areincreasingly utilized in communication systems to efficientlycommunicate digital data, and the use of such techniques has facilitatedthe increased data thruput rates.

[0003] Multimedia communications, for instance, are exemplary of newtypes of communications permitted as a result of the improvements incommunications technologies. Multimedia communications refer, generally,to the communication of more than one type of data between a sendingstation and a receiving station. Typically, the communication of suchmore than one type of data appears, to a user, to be simultaneous.Multimedia communications include, for instance, voice-over-dataapplications. Audio signals overlaid upon video signals used toeffectuate teleconferencing is an example of a multimedia communicationapplication. Two-way white board communication is exemplary of anothermultimedia communication application.

[0004] The different types of data exhibit different communicationrequirements. For instance, voice data must be communicated inreal-time. That is to say, voice data must be communicated withoutsignificant delay and must be communicated in a manner which permits itsreconstruction at a receiving station in a manner which introducesminimal time distortion. Otherwise, the voice data shall appear to benoticeably distorted. Conversely, non-voice data is not astime-sensitive. However, more stringent accuracy requirements areassociated with non-voice data.

[0005] Multimedia communications can be effectuated utilizing packetdata communication techniques. With the popularization of the Internetand communication thereon, standardized, multimedia protocols have beenset forth by which to communicate multimedia information in a formamenable to its transmission by way of the Internet. An example ofmultimedia protocol is H.323. H.323 is a widely used ITU standard whichuses RTP.

[0006] According to the H.323 protocol, when multimedia data is to betransmitted by a sending station, logical channels upon which totransmit the data are assigned. The data channels are allocatedresponsive to requests made by the sending station. Separate logicalchannels are requested for separate types of data. For instance, a firstlogical channel is requested upon which to transmit voice data, andallocation of a second logical channel is requested for transmission ofnon-voice data. A subset of the H.323 protocol, referred to as the H.245protocol, defines the manner in which the channels are requested.Packets of data are thereafter transmitted upon the logical channels. Inconventional manner, the individual packets include header information,such as IP, UDP and RTP information, to identify to where the packet isto be directed and to provide a time stamp with the packet. Theinformation of a packet of data, referred to as the payload, is appendedto the header information.

[0007] The H.323 protocol was intended originally for wirelinecommunications, such as between communication stations, connected bywireline connections including those of the Internet. But, advancementsin communication technologies have also permitted the widespread usageof radio communication systems. A cellular communication system isexemplary of a wireless communication system which has achieved widelevels of popularity and usage. Telephonic communication by way of acellular communication system mimics communication by way of aconventional wireline, telephonic system. However, because a radio-linkis utilized in a cellular, or other radio, communication system,bandwidth considerations are generally more significant than whenwireline networks are utilized for communications. That is to say, theradio-link upon which communication is communicated in a radiocommunication system is of a limited bandwidth capacity. And, byreducing the bandwidth requirements of information communicated thereon,the information capacity of the radio-link can be increased. So, effortsare made to minimize the bandwidth requirements of signals transmittedover the radio-link.

[0008] Information communicated pursuant to an H.323 protocol ispredicated upon a packet-data configuration. The header informationrequired of each packet of data is relatively bandwidth-consumptive. Asa result, communication of multimedia information by way of aradio-link, such as that formed in the operation of a cellularcommunication system, is a relatively inefficient manner by which tocommunicate multimedia information. However, because the RTP-basedprotocol has become a de facto standard by which to format multimediainformation, multimedia stations shall likely continue to be operablepursuant to such protocol irrespective of the bandwidth inefficiency ofcommunication of packet data by way of the radio-link.

[0009] If a manner could be provided by which more efficiently tocommunicate multimedia information by way of a radio-link, while stillutilizing the RTP-based protocol at the sending and receiving stations,improved multimedia communications by way of a radio communicationsystem could result.

[0010] It is in light of this background information related tomultimedia communications that the significant improvements of thepresent invention have evolved.

SUMMARY OF THE INVENTION

[0011] The present invention, accordingly, advantageously providesapparatus, and an associated method, for converting real-time multimediainformation formatted in packet-data form, into a form to facilitatetransmission of the information on a radio channel. Through suchconversion, the multimedia information can be transmitted with minimaltime delay while also being transmitted upon the radio channel in aspectrally efficient manner.

[0012] In one aspect of the present invention, real-time media, which ispart of multimedia information, is communicated between sending andreceiving multimedia stations. On the communications path between thesending and receiving stations there is a communications link, such as aradio link, that has bandwidth limitations and spectrum efficiencyrequirements. In what follows, that link shall, at times, be referred toas the communications link. The multimedia information, when generatedat a sending multimedia station, and when provided to a receivingmultimedia station, is formatted in packet-data form according to anexisting RTP protocol. Before transmission on the communications link,real-time media is converted into a communications-link format. Onceconverted into the communications-link format, the real-time media canbe transmitted upon a special channel on the communications-link in anefficient manner. Once received, the real-time media is converted out ofthe communications-link format and back into the packet-data formatbefore being sent to the receiving station. The same process takes placein the reverse direction. A special channel is defined as a channel thatprovides a constant bit rate. In a CDMA (code-division, multiple-access)communication system, the channel can be realized by a unique code bywhich the information to be communicated is encoded. In a TDMA(time-division, multiple-access) communication system, the channel canbe realized by a time slot-frequency combination. Other ways to realizea special channel are possible.

[0013] A typical example of communications link is a radio link.

[0014] Consider the example of a cellular multimedia stationcommunicating with a wireline multimedia station. At the cellularstation, the outgoing multimedia information is converted into aradio-link format. Once converted into the radio-link format, themultimedia information can be transmitted upon the radio-link in anefficient manner. Once received, the multimedia information is convertedout of the radio-link format and back into the packet-data format beforebeing sent to the wireline station. The reverse process takes place inthe reverse direction.

[0015] In one implementation, the multimedia stations include multimediaterminals. The multimedia terminals are operable to generate, and toreceive, multimedia information formatted pursuant to a multimediaprotocol such as H.323. Multimedia information is communicated betweenthe multimedia terminals by way of a radio communication system, such asa cellular communication system.

[0016] Operation of an embodiment of the present invention converts thepacket data-formatted information into a form to permit its efficienttransmission upon a channel defined in the cellular communicationsystem. The multimedia protocol provides for two components, a controlplane and a user plane. The control plane includes an applicationsignaling protocol, such as H.245 for H.323. The application signalingprotocol specifies logical channels to be opened for the communicationof the different types of multimedia information. Operation of anembodiment of the present invention monitors the application signalingand detects the opening and closing of logical channels defined in thecontrol plane. Messaging to open a real-time media channel is translatedinto messaging to set up a special channel upon which to communicatemultimedia information between the multimedia stations. Monitoringcontinues, and when the application signaling indicates that the logicalchannels are to be closed, the corresponding special channel is alsoclosed.

[0017] As the multimedia protocol such as H.323 is increasingly beingused in Internet Protocol (IP)-based communication systems to effectuatemultimedia communications, operation of an embodiment of the presentinvention advantageously permits multimedia devices, operable pursuantto the protocol, to operate without alteration. Apparatus of anembodiment of the present invention monitors signals generated by suchexisting multimedia devices, and utilizes such signals to convert themultimedia information into a form more amenable for transmission upon acircuit-switched, or other, radio channel. Overhead data, such as IP,RTP and UDP headers associated with each packet of data, is removedprior to transmission of the multimedia information upon the specialchannel. Subsequent to transmission upon the special channel, multimediainformation is reconverted back into packet-data format, and the headerinformation is affixed again to the packets of data. Because the headerinformation, otherwise forming a portion of each packet of data, isremoved prior to transmission of the payload data, the same informationis not repeatedly transmitted on the special channel. Improved spectrumefficiency results.

[0018] In these and other aspects, therefore, apparatus, and anassociated method, is provided for converting packet-formattedmultimedia information into a radio-link format. Once converted into theradio-link format, the multimedia information is amenable fortransmission upon a radio-link extending between a first communicationstation and a second communication station of a radio communicationsystem. A detector is coupled to receive indications of thepacket-formatted data. The detector detects control plane informationassociated with the packet-formatted data. A requester is coupled toreceive indications of detection by the detector of the control planeinformation. The requester requests allocation of a special channeldefined by the radio-link extending between the first and secondcommunication stations, respectively, for communication of themultimedia information thereon. A format converter is coupled to receivethe packet-formatted data of which the multimedia information is formed.Responsive to allocation of the special channel requested by therequester, the format converter converts the packet-formatted data intothe radio-link format. Thereafter, transmission of the multimediainformation, formatted in the radio-link format, is permitted upon thespecial channel.

[0019] A more complete appreciation of the present invention and thescope thereof can be obtained from the accompanying drawings which arebriefly summarized below, the following detailed description of thepresently-preferred embodiments of the invention and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 illustrates a functional block diagram of a radiocommunication system operable pursuant to an embodiment of the presentinvention to communicate multimedia information.

[0021]FIG. 2 illustrates a functional block diagram of the control planeof the radio communication system shown in FIG. 1 constructed accordingto an embodiment of the present invention.

[0022]FIG. 3 illustrates a functional block diagram of the user plane ofthe radio communication system shown in FIG. 1 according to anembodiment of the present invention.

[0023]FIG. 4 illustrates a functional block diagram, similar to thatshown in FIG. 2, but according to another embodiment of the presentinvention.

[0024]FIG. 5 illustrates a functional block diagram similar to thatshown in FIG. 3, but according to another embodiment of the presentinvention.

[0025]FIG. 6 illustrates the format of multimedia information generatedduring operation of an embodiment of the present invention.

[0026]FIG. 7 illustrates a functional block diagram of a portion of aradio communication system, here to illustrate operation of anembodiment of the present invention during hand-off procedures.

[0027]FIG. 8 illustrates a functional block diagram of a furtherembodiment of the present invention.

[0028]FIG. 9 illustrates a method flow diagram listing the method stepsof the method of operation of an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0029] Turning first to FIG. 1, a radio communication system, showngenerally at 10, is operable to communicate multimedia informationbetween multimedia stations. In the Figure, exemplary multimediastations 12 and 14 are shown. In the exemplary implementation, the radiocommunication system 10 comprises a cellular communication system, suchas a CDMA or TDMA communication system. In other implementations, theradio communication system is formed of other types of radiocommunication systems.

[0030] Multimedia information is communicated between the multimediastation 12 and the infrastructure by way of forward and reverse linkchannels, here represented by the arrows 16 and 18. In an implementationin which the radio communication system is formed of a CDMA cellularcommunication system, the forward and reverse link channels are definedby unique codes by which signals are encoded prior to theirtransmission. And, when the radio communication system comprises a TDMA,cellular communication system, the forward and reverse channels aredefined by time slot-frequency combinations. In other implementations,the channels are defined in other manners.

[0031] The multimedia station 12 is here shown to include a multimediadevice 22 and a mobile station 24. It should be understood, of course,that the embodiment shown in the figure is exemplary. In otherimplementations, the mobile multimedia station is constructed in othermanners. The multimedia device 22 is operable to generate and receivereal-time multimedia information pursuant to a packet data format suchas the RTP protocol. In what follows, multimedia information generatedby the multimedia device 22 will at times be referred to as mobileoriginated (MO), while multimedia information received by 22 will attimes be referred to as mobile terminated (MT). In conventional manner,MO multimedia information is formatted into packets of data at themultimedia device 22. In one implementation, the packet-formatted datais converted, at the multimedia device, into a form more amenable to itstransmission upon the reverse radio-link. The form will at times bereferred to as radio-link format.

[0032] The mobile station 24 here forms a cellular radio telephoneoperable in a cellular communication system and is capable oftransceiving signals on the forward and reverse link channels 16 and 18.The mobile station 24 is here shown to be coupled to the multimediadevice 22 by way of lines 26. MO multimedia information is provided tothe mobile station 24 therethrough. As noted above, in oneimplementation, the MO packet-formatted multimedia information isconverted into a radio-link format at the multimedia device 22. Inanother implementation, such conversion is performed at the mobilestation 24. MT multimedia information transmitted upon a forward linkchannel and received at the mobile station 24 is analogously alsoconvertible out of a radio-link format and into packet-data format,either at the mobile station 24, or at the multimedia device 22,depending upon the manner in which the present invention is implemented.

[0033] The multimedia station 14 is here shown to be a fixed multimediastation, coupled to access network infrastructure 34 of a cellularcommunication system. Analogous to the multimedia station 12, themultimedia station 14 is operable to generate and receive the multimediainformation formatted pursuant to a packet data format such as the RTPprotocol. MT multimedia information is generated by 14 in packet dataformat. In one implementation, the access network infrastructure 34 isfurther operable to convert the packet data-formatted information into aradio-link format to facilitate efficient transmission of the MTmultimedia information upon the forward radio-link to the multimediastation 12. MO multimedia information, received in radio link format, isconverted by the access network infrastructure into packet data format.

[0034] The cellular system network infrastructure 34 is coupled toreceive the multimedia information formed by the multimedia station 14here by way of the lines 36. While not separately shown, the multimediastation 14 is coupled to the infrastructure 34 by way of an IP network.The infrastructure can also include elements based on GPRS (GeneralPacket Radio Service). And, also while not separately shown, theinfrastructure 34 includes, base station controllers, and basetransceiver stations. The infrastructure 34 is operable to transceivesignals on the forward and reverse channels, here represented by thearrows 16 and 18.

[0035] Associated with the user plane is the control plane. While theuser plane relates to the packet data formatted multimedia informationdescribed above, the control plane relates to the protocols used forexample to establish and tear down the multimedia call, as well as thelogical channels carrying the individual media within the call. Forexample, the user plane of H.323 is based on RTP, while the controlplane includes various application signaling protocols, especiallyH.245. The conversion to a radio-link format by 24 and 34 of the MO andMT real-time multimedia information respectively, is predicated on theknowledge that the media is real-time. The knowledge is acquired by adetection function which monitors the application signaling exchanged inthe control plane. The detection function can be located in 24. Since 24does not alter the application signaling exchanged between 22 and 14,the control plane protocols of 22 can be conventional in nature.Furthermore, because operation of an embodiment of the present inventionconverts packet data-formatted information into a radio-link formatprior to its transmission and thereafter reconverts the information inthe radio-link format back to a packet-data format, the multimediadevice 22 can be of conventional construction in the user plane as well.That is to say, the multimedia device 22 can be of conventionalconstruction to generate multimedia information pursuant to a standardmultimedia protocol such as H.323. And, because of the conversion of theinformation into a radio-link format, the multimedia information can betransmitted in a spectrally efficient fashion upon a radio-link, such asthat defined in a cellular communication system.

[0036]FIG. 2 illustrates the logical layers of the control plane of theradio communication system 10 shown in FIG. 1 according to an embodimentof the present invention. The embodiment illustrated in FIG. 2 is thatof a non-integrated configuration. That is to say, the embodiment shownin FIG. 2 is that of an implementation in which the upper logical layersof the control plane are conventional in nature, such as the upper levellayers of a laptop computer, or the like, which is operable pursuant toa multimedia protocol using RTP. such as H.323, in conventional manner,without alteration. In the illustration of FIG. 2, the stations 12 and14 and the access network infrastructure are pictured in terms ofapplication layers. Operation of the embodiment of the present inventionshown in the Figure adapts the multimedia protocol so that real-timemedia can be carried over a special air interface channel in a mannerbetter to meet the delay and spectrum efficiency requirements of a radiocommunication system.

[0037] The forward and reverse channels 16 and 18 are commonlydesignated in the Figure. When the cellular communication systemcomprises a CDMA cellular communication system, such as that describedin the IS-95 standard promulgated by the EIA/TIA, dedicated codes areused by which to encode the information prior to its transmission. And,in a TDMA cellular communication system, such as that defined in theIS-136 standard promulgated by the EIA/TIA, dedicated timeslot-frequency combinations define the channels.

[0038] Here, the multimedia station 12 is shown to include anapplication signaling layer 48. The application signaling layer isdefined pursuant to the multimedia protocol. For example, H.245 is theapplication signaling corresponding to the H.323 multimedia protocol.The layer 48 is operable, amongst other things, to request logicalchannels upon which to communicate different types of multimediainformation. For instance, a request is made to open a logical channelto communicate voice data, or to communicate non-voice data, etc.Subsequent to communication of the data, a request is made to close thelogical channel.

[0039] Signaling generated by the layer 48 is provided to a TCP layer 50which is operable to form TCP data segments. The TCP layer runs on an IPlayer 52 which is operable to format the data segments according to theIP protocols to add, e.g.. headers and trailer thereto.

[0040] Formatted data generated by the layer 52 is detected by anadaptation layer 54. The adaptation layer 54 is here shown to perform,amongst other things, detection of the signaling generated by the upperlayers. Here the function of the adaptation layer 54 to detect the datais represented by a detector 56. Responsive to detection of datagenerated by the layer 52, the adaptation layer 54 translates suchsignaling into a request to set up a special channel upon the radio-linkextending between the stations 12 and the access network infrastructure.Such function performed by the adaptation layer 54 is represented in theFigure by a requester 58.

[0041] The access network infrastructure 34 is here shown also toinclude lower layers 68 which correspond to the lower application layers66 of the multimedia station 12.

[0042] The access network infrastructure 34 further includes additionallower layers 76 to carry the application signaling. The lower layers 76permits formation of a link by way of an IP backbone 78 with lowerlayers 82 of the station 14. The access network infrastructure isfurther shown to include a real-time manager 84.

[0043] Analogous to the layers 48, 50, and 52 of the station 12, thestation 14 includes an application signaling layer 88, a TCP layer 90,and an IP layer 92. The application signaling layer 88 is definedpursuant to the multimedia protocol and is operable, amongst otherthings, to request logical channels upon which to communicationdifferent types of multimedia information. The TCP layer 90 is operableto form, and to receive, TCP data segments. And, the IP layer 92 isoperable to format data segments, and to strip formatted data segments,in conventional manner. In such manner, both the stations 12 and 14 areformed of, in part, regular multimedia protocol over IP devices. That isto say, IP packet-formatted information, formatted pursuant to amultimedia protocol can be received, and generated thereat.

[0044] In exemplary operation in which the station 12 initiatescommunications, a request to set up a special channel is generated andprovided, by way of the various layers 12, the radio links 16-18, thevarious layers of the access network infrastructure, and provided to andprocessed at the real-time manager 84 of the access networkinfrastructure. Setting up of the special channel includes setting upthe channel on the radio link as well as converter functions (describedbelow) in a user plane (also described below). After successfulprocessing, a special channel is available to carry real-time media. Therequester exchanges signaling with the real-time manager 84 over thepaths labeled (4) and (4′) in FIG. 2. In addition, H.245 (H.323application signaling) exchanged between the station 12 and a remote endpoint, here the station 14, is relayed by the access networkinfrastructure over the paths labeled (2) and (2′) in the Figure.

[0045]FIG. 3 again illustrates the radio communication system 10 shownin FIGS. 1-2, again showing multimedia stations 12 and 14 and accessnetwork infrastructure 34. FIG. 3 illustrates the user plane of anon-integrated configuration, analogous to the control plane layers ofthe non-integrated configuration shown in FIG. 2.

[0046] Here, the station 12 includes a real-time media layer 102 whichruns on top of a RTP layer 104. The RTP layer is operable, amongst otherthings, to add a time stamp to data segments generated by the real-timemedia layer 102. The time stamp specifies the time when the associatedreal-time media sample was generated. The time stamp is used by thereceiving end to correct any delay fluctuation introduced by the IPbackbone network. The RTP layer also adds a sequence number to eachpacket. The sequence number is used by the receiving end to detectpacket loss and/or missequencing and take the appropriate correctiveaction. The RTP header also includes other information, such as theSynchronization Source (SSRC). All packets coming from a SSRC are partof the same timing and sequence number space.

[0047] The RTP layer 104 runs on top of a UDP layer 106 which isoperable to format data segments applied thereto. The UDP layer 106 runsupon an IP layer 108. The IP layer 108 corresponds to the IP layer 52shown in FIG. 2. The IP layer runs upon the adaptation layer 54 whichhere is operable to perform converting functions, represented by theconverter 112. Again, the adaptation layer runs upon lower layers, hereagain represented by lower layers 66.

[0048] A special channel 114 forms during operation of an embodiment ofthe present invention interconnects the station 12 with the accessnetwork infrastructure 34. As shown, the special channel interconnectsthe lower layers 66 of the station 12 with corresponding lower layers 68of the access network infrastructure. The infrastructure 34 is hereshown to include an access network infrastructure converter 116 whichruns upon the lower layers 68. The converter 116 is also shown to runupon lower layers 76, which also were shown previously in FIG. 2. Thelower layers 76 are connected by way of the IP backbone 78 with thecorresponding lower layers 82 of the station 14.

[0049] The station 14 is here shown to include layers 122, 124, 126 and128 which correspond with the corresponding layers 102, 104, 106, and108, respectively, of the multimedia station 12.

[0050] During operation of the radio communication system, when in theuser plane, packetized real-time media generated by the multimediastation 12 is processed by the converter 112. The converter 112 removesthe RTP, UDP, and IP headers attached to the media generated by themedial 102 at the layers 104, 106, and 108, respectively. Once removed,the resultant media is provided to the lower layers 66.

[0051] The lower layers 66 are operable to perform conventional lowerlayer functions. For example, if real-time media is speech, lower layersmay perform convolutional coding, interleaving, etc. They may alsoperform multiplexing with other types of traffic and media. As a resultof processing by the converter, real-time media is transmitted in aspectrally efficient manner upon a radio link formed of the specialchannel 114. At the access network infrastructure, lower layers 68perform the inverse operations. Thereafter, the converter 116regenerates the RTP, UDP and IP headers. As the values of the UDP and IPfields do not change during a call, their values need only to be sent tothe access network infrastructureat the special channel set up time andat time of handoff to another converter.

[0052] As the values of the RTP fields change, the ANI (Access NetworkInfrastructure) converter 116 must be able to derive the correct timestamps and sequence numbers of the RTP field. In one implementation, inwhich a circuit switched mode is used for the special channel, real-timemedia is received by the converter 116 in an extremely predictablemanner. Therefore, the converter 116 is able to derive the runningvalues of the RTP time stamp and sequence numbers merely by maintaininga local clock that increments monotonically and linearly in time.

[0053] For real-time media originating at the station 14, the converter16 removes the RTP, UDP, and IP headers and generates a real-time mediastream with the timing defined by the time stamps and sequence numbersreceived from the station 14. The result is transmitted upon the specialchannel 114. The converter 112 regenerates the RTP, UDP and IP headersbased upon the same principle of a local clock.

[0054] Thereby, the mobile multimedia station 12, together with the ANIconverter 116, appears to the multimedia station 14 merely to be anotherconventional multimedia station. In spite of such appearance to themultimedia station 14, operation of an embodiment of the presentinvention converts such packet data-formatted information into aradio-link format to facilitate its transmission in a spectrallyefficient manner upon a radio-link. Once the radio-link-formattedinformation is received at the converter, the packet data-format of theinformation is regenerated.

[0055]FIG. 4 again illustrates the communication system 10, shownpreviously in FIG. 1, here again showing multimedia stations 12 and 14and the access network infrastructure 34. Here, the logical layers ofthe control plane operation are illustrated in which the logical layersare formed in an integrated configuration according to an embodiment ofthe present invention. In this implementation, modifications are made tovarious of the logical layers to facilitate efficient communication ofthe multimedia between the stations 12 and 14.

[0056] In this implementation, the station 12 is shown to include anapplication signaling layer 148 which runs directly upon an adaptationlayer 152 and also directly upon a TCP layer 154. Analogous to theadaptation layer 54 shown in the embodiment of FIGS. 2-3, the adaptationlayer performs requesting functions, represented by the requester 156.The requester 156 performs functions analogous to the requester 58 shownin FIG. 2. In this implementation, the adaptation layer 152 need notperform detection functions.

[0057] The TCP layer 154 runs upon an IP layer 158.

[0058] The radio link formed of the radio channels 16 and 18 are againpictured as a single line 16-18 in the Figure. The access networkinfrastructure 34 is logically identical to that shown in the embodimentof FIG. 2. Here, the network infrastructure is shown to include lowerlayers 168, corresponding to the lower layers 68 shown in FIG. 2, andlower layers 176 corresponding to the lower layers 76 shown in FIG. 2.The lower layers 176 are coupled by way of an IP backbone 178 with lowerlayers 182 of the multimedia station 14. And, the network infrastructure34 is again shown to include a real-time manager 184, corresponding tothe real-time manager 84 shown in FIG. 2.

[0059] The multimedia station 14 is here shown include an applicationsignaling layer 188 which runs upon a TCP layer 190 which, in turn, runsupon an IP layer 192. The layers 188, 190 and 192, form the functions ofthe layers 148, 154 and 158. respectively, of the multimedia station 12.

[0060]FIG. 5 illustrates the user plane logical layers of thecommunication system 10 of the integrated configuration. Here, again,the communication system includes a multimedia station 12 and amultimedia station 14 together with an access network infrastructure 34.Once a call is established responsive to operation of the control planefunctions, multimedia information is communicated between the multimediastations 12 and 14 by way of the user plane.

[0061] The multimedia station 12 is here shown to include two logicallayers, real-time media layer 202 and lower layers 166. A specialchannel 214 is formed to extend between the station 12 and the accessnetwork infrastructure 34. In the user plane, the access networkinfrastructure shown in FIG. 5 corresponds identically with the accessnetwork infrastructure logical layers shown in FIG. 3, here includinglower layers 168 and access network infrastructure (ANI) converter 272,and lower layers 176.

[0062] The lower layers 176 are coupled by way of an IP backbone 178with lower layers 182 of the multimedia station 14. The station 14 isfurther shown to include a real-time media layer 222, an RTP layer 224,a UDP layer 226, and an IP layer 228. Such layers correspond to thelayers 122-128, respectively, of the multimedia station 14 shown in theembodiment of FIG. 3.

[0063] In the non-integrated configuration shown in the embodiments ofFIGS. 2-3, a conventional multimedia protocol stack was included in themultimedia station. That is, the behavior of the multimedia protocolsuch as H.323, in the non-integrated configuration is not aware of theexistence of an adaptation layer. The integrated configuration shown inthe embodiment of FIGS. 4-5 permits improved optimization andstreamlining by integrating the multimedia protocol stack with theadaptation layer. The stack is integrated with the adaptation layer inboth the control plane and user plane of FIGS. 4 and 5, respectively.

[0064] In the control plane shown in FIG. 4, the application signalinglayer 148 makes a determination that a special channel is required forthe communication of real-time media. Responsive to such determination,a request is forwarded to the requester 156 of the application layer152. Thereby, need for a detector of the embodiment shown in FIG. 2 isobviated. Additionally, the adaptation layer 152 interfaces directly tothe application, above the TCP and IP layers 154 and 158. In contrast,in the non-integrated configuration shown in FIG. 2, the TCP and IPlayers are formed able the adaptation layer.

[0065] Also, in the user plane shown in FIG. 5, real-time mediagenerated at the station 12 is sent directly to the special channel 214,thereby bypassing RTP, UDP and IP layers required in the non-integratedconfiguration shown in FIG. 3, also eliminating the requirement of aconverter 112 of such non-integrated embodiment.

[0066]FIG. 6 illustrates exemplary signal formats formed duringoperation of the multimedia stations 12 and 14 shown in the embodimentsof FIGS. 2-3 and 4-5. An exemplary packet 288 of multimedia informationis shown to be generated for transmission to the multimedia station 14.The packet is formed of a header portion 292 here including an IPsection, a UDP section, and an RTP section. Appended to the headerportion is a data payload 296, such as voice data.

[0067] During operation of the embodiment of the present invention shownin FIGS. 2-3, the adaptation layer 54 is operable, amongst other things,to convert the packet-formatted data, of which the packet 288 isexemplary, into a form amenable for transmission upon a special channel,that is, a circuit-switched channel or the like, of the radiocommunication system. Once converted, the data payload 296 istransmitted upon the special channel, as indicated in the center sectionof the Figure. Once received at the access network infrastructure 34,the data is reconverted into packet form as the packet 298. Asillustrated, the packet 298 corresponds to the packet 288.

[0068]FIG. 7 also represents the radio communication system 10 of theembodiment shown in FIGS. 2, 3, 4 and 5. Here, the networkinfrastructure is shown to include two access network infrastructures302 and 304 positioned, for example, to be associated with separate,spaced-apart base stations of a cellular communication network. TheFigure is illustrative of the ability, through operation of anembodiment of the present invention, to communicate multimediainformation between two mobile multimedia stations 12.

[0069] The multimedia stations 12 are operable in control and userplanes analogous to that described with respect to FIGS. 2, 3, 4 and 5above. And, two access network infrastructures 34 are shown in theFigure, each operable relative to the stations 12 in manners describedwith respect to FIGS. 2, 3, 4 and 5 above. The separate access networkinfrastructures are coupled together by way of an IP backbone 78.

[0070]FIG. 8 illustrates a communication system 10 of a furtherembodiment of the present invention. In this implementation, multi-mediainformation is communicated between two sources and sinks, heresources/sinks 312 and 313 of multi-media information. While, in theexemplary implementation, portions of the communication links formedbetween the sources/sinks 312 and 313 are formed of special channelsformed of radio links 314-316, in other implementations, thecommunication link is formed in other manners, such as by way ofwireline connections.

[0071] For purposes of defining operation of an embodiment of thepresent invention, the communication path formed between thesources/sinks of multi-media information 312 and 313 include IP networks318, 322, and 324. In conventional manner, multimedia data iscommunicated through such IP networks by formatting the data in discretepackets, such as with the RTP, UDP, and IP headers and formattinginformation, as described above.

[0072] Communication system 10 is here shown to include a plurality ofadaptors 328 which are operable to adapt the packet data, formatted inthe formatted form into a spectrally-efficient form for communicationupon the communication links 314-316 and to convert the media, oncetransmitted in the spectrally-efficient form into packetized form forcommunication over a respective IP network 318, 322, or 324.

[0073] The communication system 10 provides for 2-way communication ofthe multi-media information between the sources/sinks 312 and 313. Eachof the adaptors 328, therefore, include an upstream adaptor portion 332and a downstream adaptor portion 334. The upstream adaptor is defined asthe device located on the same side of the radio link as the multimediasource, while the downstream adaptor is located on the same side of theradio link as the multimedia sink. The upstream adaptor portions of eachof the adaptors are operable to detect when real-time multi-media is tobe communicated upon a communication link and to request the allocationof a special channel upon the communication link to effectuate thecommunication of the real-time multi-media information thereto. Suchoperation is analogous to the operation of the adaptation layer 54described previously with respect to operation of the embodiment shownin FIG. 2. And, the upstream adaptor portions 332 are further operableto convert the packet-formatted multi-media information into spectrallyefficient form for transmission upon the special channel, once assigned.Such operation of the upstream adaptor is analogous to the operation ofthe adaptation layer 54 shown in the embodiment of FIG. 3. That is tosay, the upstream adaptor removes the RTP, UDP and IP headers

[0074] The downstream adaptor portions 334 of each of the adaptors 328are operable to detect reception of the multi-media informationtransmitted in the spectrally-efficient form upon a special channel upona communication link and to convert such communication into packet-dataform, all as described with respect to the operation of portions of theaccess network infrastructure shown in FIGS. 2-3. The downstream adaptoris operable to regenerate IP, UDP and RTP headers. The values of the UDPand IP fields do not change during a call, so their values need to besent by the upstream adaptor across the communications link (e.g.. radiolink) to the downstream adaptor only when the detector detects areal-time media logical channel setup. The downstream adaptor thenmemorizes these values. For the RTP field, the downstream adaptor mustbe able to derive the correct current time stamps and sequence numbers.If the special channel is such that real-time media is received by thedownstream adaptor in a predictable manner, i.e., at a constant rate,the downstream adaptor is able to derive the running values of the RTPtime stamp and sequence numbers just by maintaining a local clock thatincrements monotonically and linearly in time. The initial time stampvalue and sampling rate can be sent by the upstream adaptor when thedetector derives the values from monitoring the application signaling.If the sampling rate were to subsequently change, the upstream adaptordetects it from the application signaling and updates the downstreamadaptor with the new sampling rate value.

[0075] In operation of the exemplary implementation shown in FIG. 8,multi-media information sourced at the multi-media information source312 is formatted into packets of data thereat and then communicated uponthe IP network 318 and delivered to the upstream adaptor portion 332 ofthe adaptor 328 connected to the IP network 318. The upstream adaptorportion 332 requests allocation of a special channel upon thecommunication link 314-316, and the portion 332 converts the packets ofdata into spectrally-efficient form for communication upon the specialchannel. A downstream adaptor portion 334 of the adaptor 329 coupled tothe IP network 322 reformats the multimedia information received thereatto permit its communication through the IP network 322 to an upstreamadaptor portion 332 of the adaptor 330 coupled to the IP network 322.Such upstream adaptor portion requests a special channel upon asubsequent communication link 314-316 and converts the packetized datainto spectrally-efficient form for communication thereon. Adaptor 331connected to the IP network 324 includes a downstream adaptor portion334 operable to reconvert the information into packetized form forcommunication through the IP network 324, thereafter to be delivered atthe multi-media source 313.

[0076] Multi-media information sourced at the source 313 is communicatedto the multi-media source 312 in analogous but reverse manner. It shouldfurther he noted that any number of adaptor-communication link chainscan be concatenated together as necessary to interconnect multi-mediasending and receiving stations.

[0077]FIG. 9 illustrates a method shown generally at 412, of anembodiment of the present invention. The method communicates multimediainformation between a first communication station and a secondcommunication station of a radio communication system. First, and asindicated by the block 414, the multimedia information is provided inpacket-data form to the first communication station. Then, and asindicated by the block 416, control plane information associated withthe multimedia information is detected.

[0078] Then, as indicated by the block 418, allocation of a specialchannel defined upon a radio-link between the first communicationstation and the second communication station is requested. Then, and asindicated by the block 422, the multimedia information is converted intoa radio-link format, amenable for transmission upon the special channel.And, as indicated by the block 424, the multimedia information istransmitted upon the special channel to the second communicationstation. Thereby, through of operation of an embodiment of the presentinvention, a manner is provided by which to efficiently transmitmultimedia information, generated pursuant to a multimedia protocolusing RTP such as H.232 upon a radio-link, such as that formed in acellular communication system. The multimedia information is convertedinto a form amenable for transmission upon the radio-link in aspectrally-efficient manner.

[0079] A fixed multimedia station sends and receives multimediainformation in packet data format, in accordance with H.323 or anotherprotocol with similar concepts of logical channels. An access networkinfrastructure is provided so that the mobile multimedia station cansend and receive multimedia information in a format more adapted to theradio link. The access network infrastructure takes care of thenecessary conversion so that seen from the entity corresponding with themobile multimedia station, the mobile multimedia station plus accessnetwork infrastructure combination behaves like a fixed multimediastation. The various entities on the communication path are mobilemultimedia station—cellular infrastructure which contains the accessnetwork infrastructure—IP network—fixed multimedia station. Anembodiment of the present invention also applies to the case of mobilemultimedia station to mobile multimedia station communication, in whichcase the entities on the path are: first mobile multimediastation—cellular infrastructure, which contains the access networkinfrastructure associated with the first station—IP network—cellularinfrastructure which contains the access network infrastructureassociated with the second station—second mobile multimedia station.

[0080] The previous descriptions are of preferred examples forimplementing the invention, and the scope of the invention should notnecessarily be limited by this description. The scope of the presentinvention is defined by the following claims:

We claim:
 1. In a first communication station operable in a radiocommunication system in which multimedia information is communicatedbetween the first communication station and a second communicationstation, an improvement of apparatus for converting packet-formatteddata, of which the multimedia information is formed, into a radio-linkformat, amenable for transmission upon a radio-link to the secondcommunication station, said apparatus comprising: a detector coupled toreceive indications of the packet-formatted data, said detector fordetecting control plane information associated with the packet-formatteddata; a requester coupled to receive indications of detection by saiddetector of the control plane information, said requester for requestingallocation of a special channel defined when the radio-link extendingbetween the first and second communication stations, respectively, forcommunication of the multimedia information therebetween; a formatconverter coupled to receive the packet-formatted data of which themultimedia information is formed, and responsive to allocation of thespecial channel requested by said requester, said format converter forconverting the packet-formatted data into the radio-link format,thereafter to permit transmission of the multimedia information,formatted in the radio-link format upon the special channel.
 2. Theapparatus of claim 1 wherein the indications of the control planeinformation to which said detector is coupled to receive comprisesindications of selective assignation-requests for logical channels uponwhich the generate the multimedia information.
 3. The apparatus of claim2 wherein the multimedia information comprises a first information-typeand at least a second information-type, and wherein the indications ofthe selective assignation-requests comprises a request for selectiveassignation of a first logical channel upon which to generate themultimedia information of the first information-type.
 4. The apparatusof claim 3 wherein the first information-type of the multimediainformation comprises real-time media, such as conversational voiceinformation.
 5. The apparatus of claim 3 wherein the indications of theselective assignation-requests comprises a request for selectiveassignation of a second logical channel upon which to generate themultimedia information of the second information-type.
 6. The apparatusof claim 5 wherein the second information-type of the multimediainformation comprises non-real-time media.
 7. The apparatus of claim 3wherein the packet-formatted data of which the multimedia information isformed further comprises user plane information including the firstinformation-type and at least the second information-type, the user planinformation to be generated selectively upon the first logical channeland at least the second logical channel subsequent to assignation of thefirst logical channel and at least the second logical channel requested.8. The apparatus of claim 7 wherein the user plane information isformatted according to an RTP protocol.
 9. The apparatus of claim 1wherein the control plane information, indications of which are detectedby said detector, is formatted according to an RTP protocol.
 10. Theapparatus of claim 1 wherein the radio communication system comprises aTDMA (time-division, multiple-access) communication system in which timeframes formed of groups of time slots are defined, wherein channelsdefined in the TDMA communication system are defined, at least in part,by a time slot allocation in successive ones of the time frames, andwherein the request by said requester for allocation of the specialchannel comprises a request for allocation of at least one selected timeslot upon which to transmit the multimedia information.
 11. Theapparatus of claim 10 wherein said format converter converts thepacket-formatted data of which the multimedia information is formed intoTDMA format for transmission upon the selected time slot subsequent toallocation responsive to the request by said requester.
 12. Theapparatus of claim 1 wherein the radio communication system comprises aCDMA (code-division, multiple-access) communication system, whereinchannels defined in the CDMA communication system are defined by channelcodes, and wherein the request by said requester for allocation of thespecial channel comprises a request for allocation of at least oneselected channel code by which to encode the multimedia information. 13.The apparatus of claim 12 wherein said format converter converts thepacket-formatted data of which the multimedia information is formed intoa coded signal encoded by the at least one channel code.
 14. Theapparatus of claim 1 wherein said detector, said requester, and saidformat converter form portions of an adaptation layer of the firstcommunication station.
 15. The apparatus of claim 14 wherein the secondcommunication station further comprises an adaptation layer, a peer ofthe adaptation layer of the first communication station.
 16. Theapparatus of claim 15 wherein said adaptation layer of the secondcommunication station is operable to convert the multimedia information,received at the second communication station in radio-link format, intopacket-data format.
 17. The apparatus of claim 16 wherein the radiocommunication system comprises a cellular radio communication system,wherein the first communication station comprises a first terminalcoupled together with a mobile station and wherein said detector, saidrequester, and said format converter from portions of the mobilestation.
 18. The apparatus of claim 17 wherein the second communicationstation comprises a second terminal coupled together with networkinfrastructure of the cellular communication system, and wherein saidadaptation layer of the second communication station is formed at thenetwork infrastructure.
 19. A wireless gateway for providing multimediainformation transmitted thereto upon a special channel in radio-linkformat to a multimedia device, said wireless gateway comprising: acontrol plane information generator coupled to receive indications ofthe multimedia information, said control plane information generator forgenerating control plane information, the control plane informationcontrolling a manner by which to provide the multimedia information,once converted into packet-data form, to the multimedia device; and aformat converter coupled to receive indications of the multimediainformation in the radio-link format, said format converter forconverting the multimedia information into the packet-data form, themultimedia information, once converted into the packet-data formprovided to the multimedia device in the manner determined by thecontrol plane information.
 20. A method for communicating multimediainformation between a first communication station and a secondcommunication station, of a radio communication system, said methodcomprising: providing the multimedia information, in packet-data form,to the first communication station; detecting control plane informationassociated with the multimedia information provided during saidoperation of providing; requesting allocation of a special channeldefined upon a radio-link between the first communication station andthe second communication station; converting the multimedia information,provided during said operation in packet-data form, into a radio-linkformat, amenable for transmission upon the special channel; andtransmitting the multimedia information upon the special channel to thesecond communication station.
 21. Apparatus for a communication stationoperable in a communication system to communicate real-time media, saidapparatus comprising: a real-time media source at which the real-timemedia to be communication by the communication station is sourced; adetector coupled to receive indications when said real-time media sourcesources real-time media to be communicated by the communication station,said detector for detecting when the real-time media is to becommunicated by the communication station; and a requester coupled toreceive indications of detection by said detector of real-time media tobe communicated by the communication station, said requester forrequesting allocation of a special channel upon which to communicate thereal-time media.
 22. Apparatus for a communication station operable in acommunication system to communicate real-time media upon a specialchannel allocated to the communication station to communicate thereal-time media thereon, said apparatus comprising: a real-time mediasource at which the real-time media to be communicated by thecommunication station is sourced; a formatter coupled to receive thereal-time media sourced by said real-time media source, said formatterfor formatting the real-time media to form formatted media; a convertercoupled to said formatter to receive the formatted media, said converterfor converting the formatted media into spectrally-efficient form forcommunication upon the special channel; and a transmitter coupled tosaid converter to receive spectrally-efficient formed media formed bysaid transmitter, said transmitter for transmitting thespectrally-efficient formed media upon the special channel. 23.Apparatus for a communication station operable in a communication systemto communicate real-time media, said apparatus comprising: a real-timemedia source at which the real-time media to be communicated by thecommunication station is sourced; and a requester coupled to receiveindications when said real-time media source sources real-time media tobe communicated by the communication station, said requester forrequesting allocation of a special channel upon which to communicate thereal-time media.
 24. Apparatus for a communication station operable in acommunication system to communicate real-time media upon a specialchannel allocated to the communication station to communicate thereal-time media thereon, said apparatus comprising: a real-time mediasource at which the real-time media to be communicated by thecommunication station is sourced; and a transmitter coupled to saidreal-time media source to receive the real-time media sourced thereat,said transmitter for transmitting the real-time media upon the specialchannel.
 25. Apparatus for access network infrastructure of a radiocommunication system operable to communicate real-time mediatherethrough with a first communication station, said apparatuscomprising: a special-channel-request detector for detecting a requestby the remote station for allocation of a special channel upon which tocommunicate the real-time media, in spectrally-efficient form, thereonand for detecting formatting data associated with the real-time media;and a special channel allocator operable at least responsive todetection by said special-channel-request detector to allocate a specialchannel upon which to communicate the real-time media.
 26. The apparatusof claim 25 further comprising a formatter coupled to receive theformatting data and the real-time media, in the spectrally-efficientform, subsequent to transmission upon the special channel, saidformatter for formatting the real-time media to form formatted media.27. In a communication system having a first communication stationoperable at least to source real-time media in a selected format, animprovement of a first upstream adaptor portion of a first adaptor foradapting the real-time media formatted in the selected format tofacilitate communication of the real-time media upon a communicationlink, said first upstream adaptor portion of the first adaptorcomprising: a first detector coupled to receive indications of thereal-time media formatted in the selected format, said first detectorfor detecting when the real-time media is to be communicated upon thecommunication link; and a first requester coupled to receive indicationsof detection by said first detector of the real-time media to becommunicated upon the communication link, said first requester forrequesting allocation of a first special channel upon which tocommunicate the real-time media upon the communication link.
 28. Thefirst upstream adaptor portion of the first adaptor of claim 27 whereinsaid first detector and said first requester comprise portions of acontrol-plane adaptation layer.
 29. The first upstream adaptor portionof the first adaptor of claim 27 further comprising a first convertercoupled to receive the real-time media formatted in the selected format,said first converter for converting the real-time media formatted in theselected format into spectrally-efficient form for communication uponthe first special channel.
 30. The first upstream adaptor portion of thefirst adaptor of claim 29 wherein the selected format in which thereal-time media sourced by the first communication station is formattedinto packets which include IP, UDP, and RTP headers and wherein thespectrally-efficient form into which said first converter converts thereal-time media comprises a real-time media stream having a timingdefined by time stamps and sequence numbers taken from the RTP headersof the packets of the real-time media.
 31. In the communication systemof claim 30 a further improvement of a first downstream adaptor portionof a second adaptor for adapting the real-time media, communicated inthe spectrally-efficient form upon the first special channel upon thecommunication link, to be formatted back into the selected format, saidfirst downstream adaptor portion of the second adaptor comprising: afirst reconverter coupled to receive the real-time media communicatedupon the special channel of the communication link, said firstreconverter for converting the real-time media into formatted form,formatted pursuant to the selected format.
 32. The first downstreamadaptor portion of the second adaptor of claim 31 wherein said firstreconverter comprises a regenerator for regenerating the real-time mediaformatted into the packets which include the IP, UDP, and RTP headers.33. In the communication system of claim 32 further comprising a secondcommunication station also operable at least to source real-time mediain the selected format, a further improvement of a second upstreamadaptor portion of the second adaptor for adapting the real-time mediasourced by the second communication station, said second upstreamadaptor portion of said second adaptor comprising: a second detectorcoupled to receive indications of the real-time media sourced by thesecond communication station, said second detector for detecting whenthe real-time media sourced by the second communication station is to becommunicated upon the communication link; and a second requester coupledto receive indications of detection by said second detector of thereal-time media sourced by the second communication station, said secondrequester for requesting allocation of a second special channel uponwhich to communicate the real-time media sourced by the secondcommunication station upon the communication link.
 34. The secondupstream adaptor portion of said second adaptor of claim 33 furthercomprising a second converter coupled to receive the real-time mediasourced by the second communication station, said second converter forconverting the real-time media sourced by the second communicationstation into spectrally-efficient form for communication upon the secondspecial channel.
 35. In the communication system of claim 34, a furtherimprovement of a second downstream adaptor portion of the first adaptorfor adapting the real-time media, sourced by the second communicationstation and communicated in the spectrally-efficient form upon thesecond special channel, to be formatted back into the selected format,said second downstream adaptor portion having a second reconvertercoupled to receive the real-time media communicated upon the secondspecial channel, said second reconverter for converting the real-timemedia into formatted form, formatted pursuant to the selected format.36. In the communication system of claim 27 a further improvement of asecond upstream adaptor portion of a second adaptor also for adaptingthe real-time media sourced by the first communication station andformatted in the selected format a mobile station selectably connectableby way of the communication link with a selected one of the firstadaptor and the second adaptor, and wherein format information relatedto the real-time media is transferable between the first adaptor and thesecond adaptor.
 37. A method for adapting real-time media, formatted ina selected format and sourced at a first communication station operablein a communication system, to facilitate communication of the real-timemedia upon a communication link, said method comprising: detecting whenthe real-time media is to be communicated upon the communication link;and requesting allocation of a first special channel upon which tocommunicate the real-time media upon the communication link.
 38. Themethod of claim 36 further comprising the additional operations of:converting the real-time media sourced by the first communicationstation into spectrally-efficient form; and transmitting the real-timemedia, once converted during said operation of converting, upon thespecial channel.
 39. In a communication system where multimediainformation is transferred from a multimedia source to a multimediasink, and a communications link is established on the path from thesource to the sink, an apparatus for converting packet-formatted data,of which the multimedia information is formed, into acommunications-link format, amenable for transmission upon acommunications-link, and for converting thecommunications-link-formatted multimedia data back into packet-formatteddata for delivery to the sink, said apparatus comprising an upstreamadaptor and a downstream adaptor; the upstream adaptor comprising: adetector for detecting when the source intends to start a real-timemedia session, and when the real-time session is to be terminated; arequester coupled to receive indications of session start by saiddetector, said requester for requesting allocation of a special channelupon which to communicate the real-time media upon the communicationslink the requester also requests deallocation of the special channelpreviously allocated, upon indications of session termination by saiddetector; a format converter coupled to receive the packet-formatteddata of which the multimedia information is formed, and responsive toallocation of the special channel requested by said requester, saidformat converter for converting the packet-formatted data into thecommunications -link format, thereafter to permit transmission of themultimedia information, formatted in the communications-link format uponthe special channel; and the downstream adaptor comprising: a real-timemanager to process the special channel allocation and deallocationrequest from the requester, and grant and release the special channelrespectively a downstream format converter coupled to receive thecommunications-link formatted data of which the multimedia informationis formed, and responsive to allocation of the special channel requestedby said requester said format converter for converting thecommunications -link-formatted data into the packet format, thereafterto permit delivery of the multimedia information to the sink in packetformat.
 40. The apparatus of claim 39 wherein the application signalingprotocol is such that the detector can detect the occurrence ofselective assignation-requests and deassignation requests for logicalchannels upon which to carry real-time media.
 41. The apparatus of claim40 wherein the application signaling protocol is H.245, and the detectordetects the occurrence of a real-time media logical channel opening andclosing.
 42. The apparatus of claim 39 where the upstream adaptor needsto send the IP and UDP header values only at special channel allocationtime; the downstream adaptor regenerates the IP and UDP headers for eachof the subsequent packets by retrieving locally stored values,previously sent by the upstream adaptor at special channel allocationtime.
 43. The apparatus of claim 39 wherein the packet format ofreal-time media in the user plane includes headers containing timestampsand sequence numbers.
 44. The apparatus of claim 43 where the upstreamformat converter generates a real-time media stream with the timingdefined by the time stamps and sequence numbers received and the specialchannel is such that the timing is preserved when received at thedownstream converter.
 45. The apparatus of claim 44 where the upstreamadaptor needs to send the initial time stamps and sequence numbers onlyat special channel allocation time; the downstream adaptor subsequentlyregenerates the current time stamp and sequence number for each of thepackets by using the initial values and the output of a local clock thatincrements monotonically and linearly in time.
 46. The apparatus ofclaim 45 where the upstream adaptor updates the downstream adaptor withnew relevant values whenever the parameters that drive the determinationof the time stamps and sequence numbers have changed; an example of suchparameters is the frequency of the clock to be used at the downstreamadaptor.
 47. The apparatus of claim 46 wherein the real-time media inthe user plane is formatted according to the RTP protocol; timestampsand sequence numbers are RTP timestamps and RTP sequence numbers. 48.The apparatus of claim 39 wherein the packet format of real-time mediain the user plane includes headers containing parameters other thantimestamps and sequence numbers; these parameters varying more slowlythan timestamps and sequence numbers.
 49. The apparatus of claim 48where the downstream adaptor regenerates more slowly varying parametersby retrieving locally stored values previously sent by the upstreamadaptor at special channel allocation time, and updated by the upstreamadaptor whenever the values change.
 50. The apparatus of claim 49wherein the real-time media in the user plane is formatted according tothe RTP protocol; more slowly varying parameters include the SSRC. 51.The apparatus of claim 39 wherein the communications link is a TDMA(time-division, multiple-access) radio link in which time frames formedof groups of time slots are defined, wherein channels defined in theTDMA communication system are defined, at least in part, by a time slotallocation in successive ones of the time frames; and wherein therequest by said requester for allocation of the special channelcomprises a request for allocation of at least one selected time slotupon which to transmit the multimedia information.
 52. The apparatus ofclaim 51 wherein said format converter converts the packet-formatteddata of which the multimedia information is formed into TDMA format fortransmission upon the selected time slot subsequent to allocationresponsive to the request by said requester.
 53. The apparatus of claim39 wherein the communications link is a CDMA (code-division,multiple-access) radio link, wherein channels defined in the CDMAcommunication system are defined by channel codes, and wherein therequest by said requester for allocation of the special channelcomprises a request for allocation of at least one selected channel codeby which to encode the multimedia information.
 54. The apparatus ofclaim 53 wherein said format converter converts the packet-formatteddata of which the multimedia information is formed into a coded signalencoded by the at least one channel code.
 55. The apparatus of claim 39where a special channel carrying real-time media can be multiplexed withother special channels carrying real-time media and/or other types ofchannels.
 56. The apparatus of claim 55 where it is not required to sendadditional header information to identify a special channel; a specialchannel can be identified by a TDMA time slot or a CDMA channel code.57. The apparatus of claim 56 where a dedicated TDMA time slot otdedicated CDMA channel code provides low and constant delay forreal-time media.
 58. In a communication system where multimediainformation is transferred between a multimedia mobile station,consisting of a multimedia device and an MS adaptor, and a multimediaremote terminal, an apparatus for converting packet-formatted data, ofwhich the multimedia information is formed, into a radio-link format,amenable for transmission upon a radio-link, and for converting theradio-link-formatted multimedia data back into packet-formatted data fordelivery to the terminal and mobile station, said apparatus comprising amobile station (MS) adaptor and a access network infrastructure (ANI)adaptor; the MS adaptor comprising: a detector for detecting when the MSor remote terminal intends to start a real-time media session, and whenthe real-time session is to be terminated; the session can be for mobileoriginated, mobile terminated or both mobile originated and mobileterminated multimedia; a requester coupled to receive indications ofsession start by said detector, said requester for requesting allocationof a special channel upon which to communicate the real-time media uponthe radio-link; the requester also requests deallocation of the specialchannel previously allocated, upon indications of session termination bysaid detector; a format converter coupled to receive the mobileoriginated packet-formatted data of which the multimedia information isformed, and responsive to allocation of the special channel requested bysaid requester, said format converter for converting thepacket-formatted data into the radio-link format, thereafter to permittransmission of the multimedia information, formatted in the radio-linkformat upon the special channel; said format converter also coupled toreceive the mobile terminated radio-link formatted data of which themultimedia information is formed, and responsive to allocation of thespecial channel requested by said requester, said format converter forconverting the radio-link-formatted data into the packet format,thereafter to permit delivery of the multimedia information to themobile multimedia device in packet format the ANI adaptor comprising: areal-time manager to process the special channel allocation anddeallocation request from the requester, and grant and release thespecial channel respectively an ANI format converter coupled to receivethe mobile originated radio-link formatted data of which the multimediainformation is formed, and responsive to allocation of the specialchannel requested by said requester, said format converter forconverting the radio-link-formatted data into the packet format,thereafter to permit delivery of the multimedia information to theremote terminal in packet format; said format converter also coupled toreceive the mobile terminated packet formatted data of which themultimedia information is formed, and responsive to allocation of thespecial channel requested by said requester, said format converter forconverting the packet-formatted data into the radio-link format,thereafter to permit delivery of the multimedia information over theradio link.
 59. The apparatus of claim 58 where the MS adaptor isnon-integrated with the multimedia device, and the multimedia device canbe of conventional construction; that is, it can execute standardmultimedia protocol software, that does not have to be altered toaccount for the radio link.
 60. The apparatus of claim 59 where thestandard multimedia protocol can be H.323.
 61. The apparatus of claim 59wherein the application signaling protocol is such that the detector candetect the occurrence of selective assignation-requests anddeassignation requests for logical channels upon which to carryreal-time media.
 62. The apparatus of claim 61 wherein the applicationsignaling protocol is H.245. and the detector detects the occurrence ofa real-time media logical channel opening and closing.
 63. The apparatusof claim 59 where the ANI adaptor needs to send the IP and UDP headervalues only at special channel allocation time; the MS adaptorsubsequently regenerates the IP and UDP headers of each of the packetsfor mobile terminated multimedia by retrieving locally stored values,previously sent by the ANI adaptor at special channel allocation time.64. The apparatus of claim 59 where the MS adaptor needs to send the IPand UDP header values only at special channel allocation time; the ANIadaptor subsequently regenerates the IP and UDP headers of each of thepackets for mobile terminated multimedia by retrieving locally storedvalues, previously sent by the MS adaptor at special channel allocationtime.
 65. The apparatus of claim 64 where the MS adaptor, upondetermining that a handoff to a new ANI adaptor has occurred, sends theIP and UDP headers for mobile originated multimedia to the new ANIadaptor. The new ANI adaptor locally stores the values and retrievesthem to regenerate IP and UDP headers of subsequent packets for mobileoriginated multimedia.
 66. The apparatus of claim 59 wherein the packetformat of real-time media in the user plane includes headers containingtimestamps and sequence numbers.
 67. The apparatus of claim 66 where theMS and ANI format converter generates a real-time media stream with thetiming defined by the time stamps and sequence numbers received, and thespecial channel is such that the timing is preserved when received atthe ANI and MS converter respectively.
 68. The apparatus of claim 67where the ANI adaptor needs to send the initial time stamps and sequencenumbers only at special channel allocation time; the MS adaptorsubsequently regenerates the current time stamp and sequence number foreach of the packets by using the initial values and the output of alocal clock that increments monotonically and linearly in time.
 69. Theapparatus of claim 68 where the ANI adaptor updates the MS adaptor withnew relevant values whenever the parameters that drive the determinationof the time stamps and sequence numbers have changed; an example of suchparameters is the frequency of the clock to be used at the MS adaptor.70. The apparatus of claim 69 wherein the real-time media in the userplane is formatted according to the RTP protocol; timestamps andsequence numbers are RTP timestamps and RTP sequence numbers.
 71. Theapparatus of claim 67 where the MS adaptor needs to send the initialtime stamps and sequence numbers only at special channel allocationtime; the ANI adaptor subsequently regenerates the current time stampand sequence number for each of the packets by using the initial valuesand the output of a local clock that increments monotonically andlinearly in time.
 72. The apparatus of claim 71 where the MS adaptorupdates the ANI adaptor with new relevant values whenever the parametersthat drive the determination of the time stamps and sequence numbershave changed; an example of such parameters is the frequency of theclock to be used at the ANI adaptor.
 73. The apparatus of claim 72wherein the real-time media in the user plane is formatted according tothe RTP protocol; timestamps and sequence numbers are RTP timestamps andRTP sequence numbers.
 74. The apparatus of claim 67 where the MSadaptor, upon determining that a handoff to a new ANI adaptor hasoccurred, sends the current value of the time stamp and sequence numberfor mobile originated multimedia to the new ANI adaptor.
 75. Theapparatus of claim 74 where the ANI adaptor regenerates packet formatheaders for mobile originated multimedia by calculating the time stampsand sequence numbers from the values sent by the MS adaptor at handofftime, and from a local clock that increments monotonically and linearlyin time.
 76. The apparatus of claim 59 wherein the radio communicationsystem comprises a TDMA (time-division, multiple-access) communicationsystem in which time frames formed of groups of time slots are defined,wherein channels defined in the TDMA communication system are defined,at least in part, by a time slot allocation in successive ones of thetime frames, and wherein the request by said requester for allocation ofthe special channel comprises a request for allocation of at least oneselected time slot upon which to transmit the multimedia information.77. The apparatus of claim 76 wherein said format converter converts thepacket-formatted data of which the multimedia information is formed intoTDMA format for transmission upon the selected time slot subsequent toallocation responsive to the request by said requester.
 78. Theapparatus of claim 59 wherein the radio communication system comprises aCDMA (code-division, multiple-access) communication system, whereinchannels defined in the CDMA communication system are defined by channelcodes, and wherein the request by said requester for allocation of thespecial channel comprises a request for allocation of at least oneselected channel code by which to encode the multimedia information. 79.The apparatus of claim 78 wherein said format converter converts thepacket-formatted data of which the multimedia information is formed intoa coded signal encoded by the at least one channel code.
 80. Theapparatus of claim 59 wherein the packet format of real-time media inthe user plane includes headers containing parameters other thantimestamps and sequence numbers; these parameters varying more slowlythan timestamps and sequence numbers.
 81. The apparatus of claim 80where the MS adaptor regenerates more slowly varying parameters byretrieving locally stored values previously sent by the ANI adaptor atspecial channel allocation time, and updated by the ANI adaptor wheneverthe values change.
 82. The apparatus of claim 81 wherein the real-timemedia in the user plane is formatted according to the RTP protocol; moreslowly varying parameters include the SSRC.
 83. The apparatus of claim80 where the ANI adaptor regenerates more slowly varying parameters byretrieving locally stored values, previously sent by the MS adaptor atspecial channel allocation time, and updated by the MS adaptor wheneverthe values change.
 84. The apparatus of claim 83 wherein the real-timemedia in the user plane is formatted according to the RTP protocol; moreslowly varying parameters include the SSRC.
 85. The apparatus of claim59 where a special channel carrying real-time media can be multiplexedwith other special channels carrying real-time media and/or other typesof channels.
 86. The apparatus of claim 85 where it is not required tosend additional header information to identify a special channel; aspecial channel can be identified by a TDMA time slot or a CDMA channelcode.
 87. The apparatus of claim 86 where a dedicated TDMA time slot otdedicated CDMA channel code provides low and constant delay forreal-time media.
 88. The apparatus of claim 58 where the multimediadevice is integrated with the MS adaptor.
 89. The apparatus of claim 88wherein the application signaling protocol is such that the detector candetect the occurrence of selective assignation-requests anddeassignation requests for logical channels upon which to carryreal-time media.
 90. The apparatus of claim 89 wherein the applicationsignaling protocol is H.245, and the detector detects the occurrence ofa real-time media logical channel opening and closing.
 91. The apparatusof claim 88 where the MS adaptor needs to send the IP and UDP headervalues only at special channel allocation time; the ANI adaptorsubsequently regenerates the IP and UDP headers of each of the packetsfor mobile terminated multimedia by retrieving locally stored values,previously sent by the MS adaptor at special channel allocation time.92. The apparatus of claim 91 where the MS adaptor, upon determiningthat a handoff to a new ANI adaptor has occurred, sends the IP and UDPheaders for mobile originated multimedia to the new ANI adaptor. The newANI adaptor locally stores the values and retrieves them to recenerateIP and UDP headers for mobile originated multimedia.
 93. The apparatusof claim 88 wherein the packet format of real-time media in the userplane includes headers containing timestamps and sequence numbers. 94.The apparatus of claim 93 where the MS and ANI format convertergenerates a real-time media stream with the timing defined by the timestamps and sequence numbers received, and the special channel is suchthat the timing is preserved when received at the ANI and MS converterrespectively.
 95. The apparatus of claim 94 where the MS adaptor needsto send the initial time stamps and sequence numbers only at specialchannel allocation time; the ANI adaptor subsequently regenerates thecurrent time stamp and sequence number for each of the packets by usingthe initial values and the output of a local clock that incrementsmonotonically and linearly in time.
 96. The apparatus of claim 95 wherethe MS adaptor updates the ANI adaptor with new relevant values wheneverthe parameters that drive the determination of the time stamps andsequence numbers have changed; an example of such parameters is thefrequency of the clock to be used at the ANI adaptor.
 97. The apparatusof claim 96 wherein the real-time media in the user plane is formattedaccording to the RTP protocol; timestamps and sequence numbers are RTPtimestamps and RTP sequence numbers.
 98. The apparatus of claim 94 wherethe MS adaptor, upon determining that a handoff to a new ANI adaptor hasoccurred, sends the current value of the time stamp and sequence numberfor mobile originated multimedia to the new ANI adaptor.
 99. Theapparatus of claim 98 where the ANI adaptor regenerates packet formatheaders for mobile originated multimedia by calculating the time stampsand sequence numbers from the values sent by the MS adaptor at handofftime, and from a local clock that increments monotonically and linearlyin time.
 100. The apparatus of claim 88 wherein the radio communicationsystem comprises a TDMA (time-division, multiple-access) communicationsystem in which time frames formed of groups of time slots are defined,wherein channels defined in the TDMA communication system are defined,at least in part, by a time slot allocation in successive ones of thetime frames, and wherein the request by said requester for allocation ofthe special channel comprises a request for allocation of at least oneselected time slot upon which to transmit the multimedia information.101. The apparatus of claim 100 wherein said format converter convertsthe packet-formatted data of which the multimedia information is formedinto TDMA format for transmission upon the selected time slot subsequentto allocation responsive to the request by said requester.
 102. Theapparatus of claim 88 wherein the radio communication system comprises aCDMA (code-division, multiple-access) communication system, whereinchannels defined in the CDMA communication system are defined by channelcodes, and wherein the request by said requester for allocation of thespecial channel comprises a request for allocation of at least oneselected channel code by which to encode the multimedia information.103. The apparatus of claim 102 wherein said format converter convertsthe packet-formatted data of which the multimedia information is formedinto a coded signal encoded by the at least one channel code.
 104. Theapparatus of claim 88 wherein the packet format of real-time media inthe user plane includes headers containing parameters other thantimestamps and sequence numbers; these parameters varying more slowlythan timestamps and sequence numbers.
 105. The apparatus of claim 104where the ANI adaptor regenerates more slowly varying parameters byretrieving locally stored values, previously sent by the MS adaptor atspecial channel allocation time, and updated by the MS adaptor wheneverthe values change.
 106. The apparatus of claim 88 wherein the real-timemedia in the user plane is formatted according to the RTP protocol; moreslowly varying parameters include the SSRC.
 107. The apparatus of claim88 where a special channel carrying real-time media can be multiplexedwith other special channels carrying real-time media and/or other typesof channels.
 108. The apparatus of claim 107 where it is not required tosend additional header information to identify a special channel; aspecial channel can be identified by a TDMA time slot or a CDMA channelcode.
 109. The apparatus of claim 108 where a dedicated TDMA time slotto dedicated CDMA channel code provides low and constant delay forreal-time media.